<head>
    <link href="multiple-select.css" rel="stylesheet"/>

     
</head>
<body>
    <select id="ms" multiple="multiple">
        <option value="1">January</option>
       
        <option value="12">December</option>
    </select>
   <script type="text/javascript" src="http://code.jquery.com/jquery-2.1.0.min.js"></script>
          <script src="jquery.multiple.select.js"></script>
     <script>
     $(function() {
         $('#ms').change(function() {
             console.log($(this).val());
         }).multipleSelect({
             width: '100%'
         });
     });
    </script>
    
</body>